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Aims: Adjuvant heart failure (HF) drug therapy in patients undergoing chronic mechanical circulatory support (MCS) is often used in conjunction with a continuous-flow left ventricular assist device (LVAD), but its potential impact is not well defined. The objective of the present study was to examine the effects of conventional HF drug therapy on myocardial structure and function, peripheral organ function and the incidence of adverse events in the setting of MCS.Methods and Results: Patients with chronic HF requiring LVAD support were prospectively enrolled. Paired myocardial tissue samples were obtained prior to LVAD implantation and at transplantation for histopathology. The Meds group comprised patients treated with neurohormonal blocking therapy (concurrent beta-blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, and aldosterone antagonist), and the No Meds group comprised patients on none of these. Both the Meds (n = 37) and No Meds (n = 44) groups experienced significant improvements in cardiac structure and function over the 6 months following LVAD implantation. The degree of improvement was greater in the Meds group, including after adjustment for baseline differences. There were no differences between the two groups in arrhythmias, end-organ injury, or neurological events. In patients with high baseline pre-LVAD myocardial fibrosis, treatment with HF drug therapy was associated with a reduction in fibrosis.Conclusions: Clinical and histopathological evidence showed that adjuvant HF drug therapy was associated with additional favourable effects on the structure and function of the unloaded myocardium that extended beyond the beneficial effects attributed to LVAD-induced unloading alone. Adjuvant HF drug therapy did not influence the incidence of major post-LVAD adverse events during the follow-up period. [ABSTRACT FROM AUTHOR]

Background This study evaluated current trends in incidence and outcomes of left ventricular assist device (LVAD)-related thromboembolic (LVAD-TE) and LVAD malfunction (LVAD-M) complications among heart transplant (HT) candidates supported with continuous-flow LVADs. LVAD-TE and LVAD-M are potentially catastrophic complications that may require status upgrade on the HT waiting list. An increased incidence of device thrombosis has been recently observed; however, whether similar trends of LVAD-TE and LVAD-M are observed on the HT waiting list and their effect on outcomes is unknown. Methods We analyzed 3,821 HT candidates on continuous-flow LVADs who were registered on the United States waiting list from 2008 to 2014. We evaluated the incidence of LVAD-TE and LVAD-M as well as survival before and after HT. Results LVAD-TE occurred in 249 patients (6.5%) and LVAD-M in 210 patients (5.5%). The incidence of LVAD-TE was highest in regions 1, 2, and 9, whereas LVAD-M was highest in regions 9, 1, and 7. The incidence of LVAD-TE and LVAD-M increased after 2011 from 0.04 to 0.10 and from 0.03 to 0.08 events per patient-year ( p < 0.0001 for both comparisons). Survival on the waiting list at 2 years was lower in candidates with LVAD-TE (45% vs 72%, p < 0.0001) and LVAD-M (56% vs 71%, p = 0.003) compared with candidates without complications. Post-HT survival was similar between patients with and without LVAD-TE and LVAD-M ( p > 0.43 for both outcomes). In patients with LVAD-TE, mortality risk was highest among candidates managed conservatively (hazard ratio, 8.07; p < 0.0001), whereas patients who underwent HT only (hazard ratio, 0.10; p < 0.0001) had the lowest mortality risk and similar to that of patients without LVAD-TE ( p = 0.34). Conclusions The incidence of LVAD-TE and LVAD-M on the United States waiting list has increased since 2011, with significant regional variation. LVAD-TE and LVAD-M have a detrimental effect on waiting list survival and transplant candidacy. In candidates who develop an LVAD-TE, a conservative approach, without LVAD exchange or HT, carries the highest risk of death. These results should be considered in the ongoing efforts to optimize the allocation of donor hearts. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to prospectively investigate the longitudinal effects of continuous-flow left ventricular assist device (LVAD) unloading on myocardial structure and systolic and diastolic function. Background: The magnitude, timeline, and sustainability of changes induced by continuous-flow LVAD on the structure and function of the failing human heart are unknown. Methods: Eighty consecutive patients with clinical characteristics consistent with chronic heart failure requiring implantation of a continuous-flow LVAD were prospectively enrolled. Serial echocardiograms (at 1, 2, 3, 4, 6, 9, and 12 months) and right heart catheterizations were performed after LVAD implant. Cardiac recovery was assessed on the basis of improvement in systolic and diastolic function indices on echocardiography that were sustained during LVAD turn-down studies. Results: After 6 months of LVAD unloading, 34% of patients had a relative LV ejection fraction increase above 50% and 19% of patients, both ischemic and nonischemic, achieved an LV ejection fraction ≥40%. LV systolic function improved as early as 30 days, the greatest degree of improvement was achieved by 6 months of mechanical unloading and persisted over the 1-year follow up. LV diastolic function parameters also improved as early as 30 days after LVAD unloading, and this improvement persisted over time. LV end-diastolic and end-systolic volumes decreased as early as 30 days after LVAD unloading (113 vs. 77 ml/m2, p < 0.01, and 92 vs. 60 ml/m2, p < 0.01, respectively). LV mass decreased as early as 30 days after LVAD unloading (114 vs. 95 g/m2, p < 0.05) and continued to do so over the 1-year follow-up but did not reach values below the normal reference range, suggesting no atrophic remodeling after prolonged LVAD unloading. Conclusions: Continuous-flow LVAD unloading induced in a subset of patients, both ischemic and nonischemic, early improvement in myocardial structure and systolic and diastolic function that was largely completed within 6 months, with no evidence of subsequent regression. [Copyright &y& Elsevier]

Bleeding is an important cause of morbidity and mortality in patients with continuous-flow left ventricular assist devices (LVADs). Reduced pulsatility has been implicated as a contributing cause. The aim of this study was to assess the effects of different degrees of pulsatility on the incidence of nonsurgical bleeding.The Utah Transplantation Affiliated Hospitals (U.T.A.H.) heart failure and transplant program databases were queried for patients with end-stage heart failure who required support with the continuous-flow LVAD HeartMate II (Thoratec Corp, Pleasanton, CA) between 2004 and 2012. Pulsatility was evaluated by means of the LVAD parameter pulsatility index (PI) and by the echocardiographic assessment of aortic valve opening during the first 3 months of LVAD support. PI was analyzed as a continuous variable and also stratified according to tertiles of all the PI measurements during the study period (low PI: <4.6, intermediate PI: 4.6-5.2, and high PI: >5.2). Major nonsurgical bleeding associated with a decrease in hemoglobin ≥2 g/dL (in the absence of hemolysis) was the primary end point. A total of 134 patients (median age of 60 [interquartile range: 49-68] years, 78% men) were included. Major bleeding occurred in 33 (25%) patients (70% gastrointestinal, 21% epistaxis, 3% genitourinary, and 6% intracranial). In multivariable analysis, PI examined either as a categorical variable, low versus high PI (hazard ratio, 4.06; 95% confidence interval, 1.35-12.21; P=0.04), or as a continuous variable (hazard ratio, 0.60; 95% confidence interval, 0.40-0.92; P=0.02) was associated with an increased risk of bleeding.Reduced pulsatility in patients supported with the continuous-flow LVAD HeartMate II is associated with an increased risk of nonsurgical bleeding, as evaluated by PI. [ABSTRACT FROM AUTHOR]

Background Mechanical circulatory support (MCS) leads to favorable changes in the failing heart at the molecular, cellular, and structural levels. However, myocardial recovery leading to device explantation is rare. We reasoned that the multicenter United Network for Organ Sharing (UNOS) registry might provide insights into clinical predictors and outcomes of the recovery process. Methods The MCS device data set of the UNOS registry was queried for patients with long-term continuous-flow left ventricular assist devices (CF-LVADs) that were explanted for heart transplantation or indication of recovery. Analysis was restricted to adult patients (≥18 years old) who were listed for an initial heart transplantation. Patients with CF-LVADs that were explanted because of recovery were compared with patients with CF-LVADs who underwent transplantation. Results We identified 594 patients with HeartMate II devices and 92 patients with HeartWare devices. Duration of support was on average 500.4 ± 325.3 days. In 34 (5.0%) patients, devices were explanted secondary to myocardial recovery. Univariate predictors of recovery in patients with long-term LVADs included younger age (40 years vs 53 years), female sex, lower body mass index (25.7 kg/m 2 vs 27.9 kg/m 2 ), non-ischemic etiology (91% vs 59%), lack of implantable cardioverter defibrillator at the time of listing (44% vs 79%), and lower serum creatinine (0.97 mg/dl vs 1.28 mg/dl) (all p < 0.05). In the post-explantation period, freedom from death or transplantation was 66% at 1 year. Conclusions The incidence of recovery on device support is low in the current MCS era and limited to a select cohort of predominantly young patients with non-ischemic myopathy. Given the high incidence of disease recurrence, patients should be closely followed after device explantation. [ABSTRACT FROM AUTHOR]

Background: Significant improvements in myocardial structure and function have been reported in some patients with advanced heart failure (termed responders [R]) following left ventricular assist device (LVAD)-induced mechanical unloading. This therapeutic strategy may alter myocardial energy metabolism in a manner that reverses the deleterious metabolic adaptations of the failing heart. Specifically, our previous work demonstrated a post-LVAD dissociation of glycolysis and oxidative-phosphorylation characterized by induction of glycolysis without subsequent increase in pyruvate oxidation through the tricarboxylic acid cycle. The underlying mechanisms responsible for this dissociation are not well understood. We hypothesized that the accumulated glycolytic intermediates are channeled into cardioprotective and repair pathways, such as the pentose-phosphate pathway and 1-carbon metabolism, which may mediate myocardial recovery in R.Methods: We prospectively obtained paired left ventricular apical myocardial tissue from nonfailing donor hearts as well as R and nonresponders at LVAD implantation (pre-LVAD) and transplantation (post-LVAD). We conducted protein expression and metabolite profiling and evaluated mitochondrial structure using electron microscopy.Results: Western blot analysis shows significant increase in rate-limiting enzymes of pentose-phosphate pathway and 1-carbon metabolism in post-LVAD R (post-R) as compared with post-LVAD nonresponders (post-NR). The metabolite levels of these enzyme substrates, such as sedoheptulose-6-phosphate (pentose phosphate pathway) and serine and glycine (1-carbon metabolism) were also decreased in Post-R. Furthermore, post-R had significantly higher reduced nicotinamide adenine dinucleotide phosphate levels, reduced reactive oxygen species levels, improved mitochondrial density, and enhanced glycosylation of the extracellular matrix protein, α-dystroglycan, all consistent with enhanced pentose-phosphate pathway and 1-carbon metabolism that correlated with the observed myocardial recovery.Conclusions: The recovering heart appears to direct glycolytic metabolites into pentose-phosphate pathway and 1-carbon metabolism, which could contribute to cardioprotection by generating reduced nicotinamide adenine dinucleotide phosphate to enhance biosynthesis and by reducing oxidative stress. These findings provide further insights into mechanisms responsible for the beneficial effect of glycolysis induction during the recovery of failing human hearts after mechanical unloading. [ABSTRACT FROM AUTHOR]

Background: Small-scale studies focused mainly on nonischemic cardiomyopathy (NICM) have shown that a subset of left ventricular assist device (LVAD) patients can achieve significant improvement of their native heart function, but the impact of ischemic cardiomyopathy (ICM) has not been specifically investigated. Many patients with acute myocardial infarction are discharged from their index hospitalization without heart failure (HF), only to return much later with overt HF syndrome, mainly caused by chronic remodeling of the noninfarcted region of the myocardium.Objectives: This study sought to prospectively investigate the effect of ICM HF etiology on LVAD-associated improvement of cardiac structure and function using NICM as control.Methods: Consecutive patients (n = 154) with documented chronic and dilated cardiomyopathy (ICM, n = 61; NICM, n = 93) requiring durable support with continuous-flow LVAD were prospectively evaluated with serial echocardiograms and right heart catheterizations.Results: In patients supported with LVAD for at least 6 months, we found that 5% of subjects with ICM and 21% of subjects with NICM achieved left ventricular ejection fraction ≥40% (p = 0.034). LV end-diastolic and end-systolic volumes and diastolic function were significantly and similarly improved in patients with ICM and NICM.Conclusions: LVAD-associated unloading for 6 months resulted in a substantial improvement in myocardial structure, and systolic and diastolic function in 1 in 20 ICM and 1 in 5 NICM patients. These specific incidence and timeline findings may provide guidance in clinical practice and research design for sequencing and prioritizing advanced HF and heart transplantation therapeutic options in patients with ICM and NICM. [ABSTRACT FROM AUTHOR]

Background In animal models of heterotopic transplantation, mechanical unloading of the normal, nonhypertrophic heart results in atrophy. Primarily on the basis of these animal data, the notion that chronic left ventricular assist device (LVAD)-induced unloading will result in atrophy has dominated the clinical heart failure field, and anti-atrophic drugs have been used to enhance the cardiac recovery potential observed in some LVAD patients. However, whether unloading-induced atrophy in experimental normal heart models applies to failing and hypertrophic myocardium in heart failure patients unloaded by continuous-flow LVADs has not been studied. Objectives The study examined whether mechanical unloading by continuous-flow LVAD leads to myocardial atrophy. Methods We prospectively examined myocardial tissue and hemodynamic and echocardiographic data from 44 LVAD patients and 18 untransplanted normal donors. Results Cardiomyocyte size (cross-sectional area) decreased after LVAD unloading from 1,238 ± 81 μm 2 to 1,011 ± 68 μm 2 (p = 0.001), but not beyond that of normal donor hearts (682 ± 56 μm 2 ). Electron microscopy ultrastructural evaluation, cardiomyocyte glycogen content, and echocardiographic assessment of myocardial mass and left ventricular function also did not suggest myocardial atrophy. Consistent with these findings, t-tubule morphology, cytoplasmic penetration, and distance from the ryanodine receptor were not indicative of ongoing atrophic remodeling during LVAD unloading. Molecular analysis revealed no up-regulation of proatrophic genes and proteins of the ubiquitin proteasome system. Conclusions Structural, ultrastructural, microstructural, metabolic, molecular, and clinical functional data indicated that prolonged continuous-flow LVAD unloading does not induce hypertrophy regression to the point of atrophy and degeneration. These findings may be useful in designing future investigations that combine LVAD unloading and pharmaceutical therapies as a bridge to recovery of the failing heart. [ABSTRACT FROM AUTHOR]